The long-term objective of this core is to provide investigators interested in environmental lung disease the resources and technical expertise required to conduct in vivo mechanistic studies in mice. The following core services will be provided: 1) importation and exportation of mice, 2) breeding of wild type mice for mechanistic studies, 3) breeding and genotying of genetically manipulated mouse lines for use in mechanistic studies, 4) development of allergic mice using both acute and chronic sensitization/challenge protocols, 5) exposure of animals to model environmental pollutants, 6) treatment interventions to test the efficacy, toxicity, and mechanisms of action of novel therapies, and 7) physiological phenotyping of mice after the induction of environmental lung disease for evaluation of airway resistance, compliance, and airway hyperresponsiveness to methacholine. This core supports the mission of NIAID to study genetic and environmental interactions as they relate to environmental lung disease. Mechanistic studies in animals, particularly the use of genetically manipulated mice, is essential for the development of new therapies to improve public health.